That's why doing this opening in Notepad is not usually wise.
Remember - even if you add or remove something and then put it back, it will still corrupt the file. This is because Notepad doesn't understand the structure of EXE program files. It's a fun thing to try when starting out, but please bear in mind that the EXE file that you open, can't be displayed correctly, and if ANY change is made in notepad, if you save the file, it will destroy (corrupt) the EXE program and it won't work anymore.
